The present invention relates to portable spray painting equipment, particularly known as hand-held paint cup guns used for airless spraying of paint and other coating materials. A prior art cup gun 10 may be seen in FIG. 1. Gun 10 includes a spray tip 12, a gun body 14, a handle 16, a power cord 18 and a piston pump housing 20. In one embodiment, a paint cup 22 is detachably secured to the pump housing 20. In this configuration a suction tube assembly 24 is positioned to draw paint from the cup 22 and deliver it to the pump (not shown) inside housing 20 for spraying via spray tip 12.
Referring now to FIG. 2, in an alternative configuration, an extended suction set 26 may be used in place of cup 22 and suction tube assembly 24. The prior art extended suction set 26 includes only a double lumen hose 28 and a double lumen fitting 30. (Although shown in FIG. 2, it is to be understood that retaining ring 54 is not a part of the prior art extended suction set, but is intended to be used therewith.) Fitting 30 has a flange 32 extending from and formed integrally with a pair of relatively rigid nipples 34, 35. Each of nipples 34, 35 preferably has one or more conical barbs thereon to retain hose 28 to nipples 34, 35.
Pump housing 20 has a paint inlet 36 for providing a path for receiving paint to be delivered to the pump in the housing 20, and a return port 38 for providing a path for paint leaking past a piston (not shown) in the pump. Housing 20 also has a retaining means 40 in the form of a plurality of lips 42-48 adapted to engage and retain the paint cup 22 to housing 20. It is to be understood that the extended suction set 26 is for use in the absence of the paint cup 22, with the elongated double lumen hose of the suction set adapted for drawing paint from a remote container (not shown) for delivery to gun 10 via nipple 35 connected to one lumen 50, and providing a closed path via nipple 34 and the other lumen 52 for paint from the return port 38 to be carried back to the remote container when the fitting 30 has nipples 35, 34 engaged between hose 28 and the paint inlet 36 and return port 38, respectively. In the prior art when the extended suction set was held to the paint pump housing only by friction of the nipples 35, 34 received in the paint inlet 36 and return port 38, the fitting 30 was observed to sometimes unexpectedly separate from housing 20, possibly because of vibration and the separating forces between the gun 10 and the weight of the extended suction set 26 occasioned by movement of the gun as spray painting took place. Any such unexpected separation is highly undesirable since it interrupts the spray painting process and will likely require clean-up because of the unexpected release of the paint from tube 50 (and possibly tube 52 as well) after hose 28 separated from gun 10.
The present invention overcomes these shortcomings of the prior art by providing an assembly which includes a locking ring 54 preventing such unintentional separation securing the extended suction set 26 to gun 10 thus therebetween.